Convective Outlook: Wed 18 May 2016
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Wed 18 May 2016 - 05:59 UTC Thu 19 May 2016

ISSUED 19:03 UTC Tue 17 May 2016

ISSUED BY: Chris

Post cold-frontal convection is expected to develop widely across the British Isles through Wednesday as an upper low and subsequent broad cold pool aloft will aid convection capable of producing a few lightning strikes across much of southern Scotland, eastern Ireland and northern and eastern England. However, overall instability will be weak, meaning the potential of lightning will remain low. 


The greatest potential for thunderstorms on Wednesday will be across the Welsh-English border and much of the West Midlands and parts of south-central and southwestern England. After the morning cold front clears eastwards cold air aloft will spread across the region and combined with some sunny spells/surface heating, CAPE values will reach 500-700 j/kg. Convection should initiate just before midday in the western edge of the SLGT area and shift eastwards through the afternoon. Overall shear remains relatively weak therefore showers and thunderstorms will be mainly of the pulse variety and thus severe weather and the chance of any significant hail is unlikely. Brief heavier downpours on ground that will have had rain earlier in the day could produce some very localised flash flooding, mainly in the SLGT region. 

All showers will be diurnal in nature and will become more isolated after 1800BST and fading away between 1900-2000BST.